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Heavy Teen Marijuana Use Causes Brain Changes

12/8/2005 Join Together

Adolescents who were heavy users of marijuana exhibited changes in their brain similar to those found in schizophrenics, Newsday reported Nov. 30.

Researchers at North Shore University Hospital-Long Island Jewish (LIJ) Healthcare System conducted brain scans on male teenagers who were daily, long-term users of marijuana, as well as adolescent schizophrenia patients who did and did not use marijuana. They found that a region of the brain called the arcuate nucleus -- which plays a role in higher cognitive function -- was atrophied in both the marijuana users and those with schizophrenia. However, the marijuana smokers were underdeveloped only on the left side of the brain, whereas the schizophrenics had atrophy on both sides of their brains.

The study may lend credence to the theory that drug use could trigger schizophrenia. "If there are people who are vulnerable and smoke marijuana, they may be putting themselves at greater risk for developing severe mental illness," said researcher Manzar Ashtari of LIJ's Zucker Hillside Hospital. "Whatever insult is happening, it is taking place in brain regions still under construction," she added, warning teens: "Don't put yourself at risk, especially if you have a family history of schizophrenia or severe mental illness -- especially when the brain is still growing."

The research was presented at the Radiological Society of North America's annual meeting in Chicago.